are there any baby heart beat apps for early pregnancy that aren't fake?

I've been hearing a lot of talks regarding the baby heart beat apps lately and it's made me wonder:
How much more effective than a at home baby heart monitor can they be when it's so hard to listen to the baby on the home monitor?
Are those apps fake? Fit with a prerecord end  sound to give us false hopes ?
If there are some that are truly not fake what app is it and what has your experience been?
Thanks!